ES2301835T3 - METHOD AND SYSTEM OF FORMATION OF IMAGES OF NIGHT VISION MOUNTED IN VEHICLE. - Google Patents

Abstract

A vehicle mounted imaging system and method, enabling selective imaging of objects in a low-visibility environment. The system includes a light source providing non-visible light pulses and a camera having an image intensifier enabled to gate selected received images. The light source may be a laser generator, which may be enabled to generate a pulse width related to the depth of a field to be imaged. The gated image intensifier may determine gating time spans according to the depth of a field to be imaged.

Description

Method and imaging system of Night vision mounted on vehicle.

Field of the Invention

The present invention is related to the field of the formation of nocturnal images and with systems of presentation in general and, more particularly, with systems of imaging and presentation, applicable to use in vehicles, and with operating methods implemented in such systems.

Background of the invention

When driving a vehicle at night, or in poor visibility conditions, insufficient lighting generated by the front lights of the vehicle and / or any ambient lighting of the road almost always limits the field of visibility of the driver. When driving, the driver needs a scope, and therefore a time, enough to identify a danger at a certain distance and to react accordingly. He scope of vision that requires an attentive driver to avoid Danger can be empirically calculated. It is customary to calculate the required range by multiplying the driving speed by the time needed for the person's combined reaction time and of the vehicle. This time can vary from 6 to 10 seconds, for highway driving, up to more than double for a heavy vehicle off the road, and even up to ten times for trains, ships or aircraft landing. For example, a driver traveling at a speed of 120 km / h (i.e. 33 m / s) would need a visibility range of approximately 200 - 333 meters

However, the vehicle's light system, even when the headlights are set to the high beam status (long lights), will generally illuminate at a distance not exceeding approximately 200 meters, that is, approximately 6 seconds of driving at a speed of 120 km / h. However, it should be noted that the use of high beam lights or alternative high power lights is not usual nor is it permissible for continuous driving, as it causes glare ("blindness") to other drivers. The situation is worse when the headlights are placed in their low beam state (short lights), since the illuminated distance does not generally exceed 100 meters, that is, around only 3 seconds of driving at a speed of 120 km / h. The situation is the worst of all while driving off the road, in a dusty environment, where visibility is below 50 meters and the time to stop can be 15-20 seconds, or when sailing a ship inside of a port with fog, with 50 meters of visibility and a reaction time of 30 - 60
seconds.

This seems to mean that drivers they are currently driving under conditions of insufficient field of visibility or, at least, in a state at the border of the scope required for safe vision, and are therefore putting themselves in danger themselves and others. The simple improvement of the lights front of the vehicle to increase the range of its lighting, it may not be an adequate solution, because the glare to other drivers, and also due to the technological limitations

With the current state of events, and as a natural result, developments in the field of equipment of imaging in aeronautical / military applications have led to the idea of introducing and integrating training systems of night images in vehicles, which could increase the driver visibility field. Moreover, the systems of presentation for images received from systems observation in poor or low vision conditions visibility, have also improved. Notable examples of that are the HUD (Presentation at the top) and LCD (Display of Liquid crystal).

A technology, which could be integrated and made operate in vehicles, is the thermal formation technology of images. A series of detectors, sensitive to radiation infrared, absorbs the heat energy emitted by the bodies, and create a video image according to the heat emission absorbed An example of training technology is described thermal imaging in U.S. Patent 5,414,439 titled "Presentation at the top with vision reinforcement nocturnal. "This patent describes the installation of a camera infrared in a vehicle, to observe the conditions of the Road using thermal imaging. The camera transmits a video signal to the HUD system, which presents the image on the windshield of the vehicle (or any other combiner optical) located in front of the operator.

The system described in patent 5,414,439 is based on a thermal camera, which does not offer a solution for perceive differences in colors and shades of gray (one camera thermal presents only differences in heat and emissivity). He system is heat sensitive and therefore does not detect temperature of the elements if it is equal to the bottom temperature of the highway. In other words, the system does not offer the driver no help reading the signals, or signal indicators, etc. Nor does the thermal camera exploit the extensive use of colors reflectors applied to road markings, lights reflective vehicles, and the like. Moreover, the camera thermal does not show visible light (works in the range of infrared remote). In addition, as the system is based on a series of infrared detectors that work in lengths of infrared remote wave (8 µm to 14 µm), it might not be possible to install the system inside the driver's compartment of the vehicle, because the windows of the vehicle do not transmit Remote infrared wavelength energy.

Consequently, considering an installation in a vehicle in order to increase the scope of vision of the driver, the disadvantages of thermal formation technology of Images are markedly evident. The system is cumbersome, sensitive to various driving states, it may not give a clear vision of "cold" road signs, and it is relatively expensive

Other technology, which could be integrated apparently and being incorporated into a vehicle, is the technology of Image intensification An intensifier intensifies the photons available at the entrance in about 50,000 to 100,000 times, and It allows observations even in a very dark environment. But nevertheless, intensification technology is prone to "florescence". The image intensifier is sensitive to photons of visible wavelengths and close to infrared. Consequently, an image intensifier can be subjected to flowering by sources with visible wavelength and near the infrared entering the field of vision.

Therefore, for installation in a vehicle, in order to increase the driver's visibility field, this Technology also has notable disadvantages. A vehicle that travels on the road you will necessarily find light coming from vehicles that approach, precedence and advance, as well as the one coming from the street lamps. These sources emit light both in the visible spectrum and in the near infrared. These  sources could cause an intensifier saturation and a Florescence of the image provided.

An additional training technology images that can be used for imaging nocturnal, is the imaging technology with door commutation. To reduce the influence of interference on the space between the imaging system and the object, it uses switched imaging, so that the energy reflected from the illuminated object is absorbed only in specified time intervals. In this way, the image presented may be influenced by the entrance to the receiver of imaging, only when the energy reflected from the illuminated object really reaches it (after having covered,  at the speed of light, the distance from the object to the receiver of pictures).

For application in an installation of vehicles that aim to increase the visibility field of the driver, the disadvantage of adding a light source is evident. For example, such technology may concern a system that requires radiation safety (for example, that meets the MPE standards requirements) and the additional light source must Be of safety levels for the eyes.

Night driving needs an increase in driver visibility field, implementing a system that can provide the driver with an extended range of observation (for example, up to 500 meters ahead). Such system may be required to operate in a saturated environment with light sources of visible wavelengths and close to infrared (for example, front lights of other cars, lights of street lamps, other active night vision systems), at the same time that overcomes the challenge of eliminating glare resulting from such sources of light, and without finding radiation or other problems of security that influence the system.

Other technologies that can be integrated and made operating in vehicles are disclosed in United States patent No. 4,708,473 and in U.S. Patent No. 3,947,119. The U.S. Patent No. 4,708,473, to Metzdorff et al. collaborators, entitled "Acquisition of scope images" It is aimed at a method to obtain images of the scope. Be they transmit short pulses of light and reflections are received from objects. The reception time is synchronized in such a way that they obtain partial images corresponding to the reflections of particular distances When combining the partial images, it Get a composite image of the scope. The states patent United nº 3,947,119 of Bamberg and other collaborators, titled "Automatic range scanning technique by active sensor", is aimed at a system to explore a wide depth of field of interest to see objects at all distances in the depth of field A plurality of range increases by means of light pulses, with energy reflected from each increase in scope that is received by a amplifier with switching door. The time between lighting pulses and switching of the light amplifier is adjust to sequentially vary the observed range. The Time settings can be used to get reinforcement, suppression or apparent uniform illumination of the increments preselected range, so that all distances from interest are observed by the light amplifier within a single integration period

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Summary of the invention

The present invention provides a system of imaging, according to claim 1, and a imaging method according to claim 39. The dependent claims define embodiments preferred and advantageous of the invention.

In particular, a system of imaging mounted on a vehicle, according to some  embodiments of the present invention, to allow the night imaging as well as imaging in conditions of poor visibility. The system is apt to be implemented in a wide variety of vehicle types, such such as cars, trucks, heavy equipment outside the road, and even on ships, trains and airplanes (hereinafter, vehicle).

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Such a system could overcome the problems of flowering of the environment, self-flowering; florescence from similar systems installed in others vehicles, and can meet the requirements of eye safety. When driving at night, a driver who observes the image of the road produced by the system could benefit from a high quality image and from a visibility field considerably expanded, compared to the field of visibility provided by the headlights of the vehicle.

According to an embodiment of the present invention, a night vision system is provided mounted on a vehicle, which may include a light source in the non-visible spectrum (for example, a laser source), in order to illuminate, for example, the environment in front of the vehicle. He night vision system can also include a camera adapted for switching images, for example, a camera with a switched image intensifier. The camera can absorb the energy of reflections from scenes illuminated by The source of light. The system may also include an apparatus for presentation to present the image produced by the reflections absorbed in the chamber.

According to another embodiment of the present invention, the system provides an optimization of the programmable gain / system sensitivity (TPG), making maximum the ability of the system to absorb energy from reflections from the far end of the depth of field to illuminate (a range from R_ {0} to R_ {max}) and to minimize capacity of the system to absorb energy from the reflections from the near end of the depth of field to be illuminated (a range from R_ {min} to R_ {0}).

According to another embodiment of the present invention, the light source in the non-visible spectrum is a laser generator, which has a pulse width that is related to the depth of field a
to illuminate.

According to an additional embodiment of the present invention, the length of time in which connect the camera ("ON"), (absorbing reflections from illuminated objects) is determined according to the depth of the field to be illuminated. The depth of field to be illuminated can be considered as the selected scope from which they must be absorbed reflections (R_ {min} to R_ {max}).

The opening time of an intensifier of switched images (T II), for example, can be calculated by the depth of field whose lighting is desired, multiplied by two, and divided by the speed of light (C). The time in which the field intensifier is switched on ("ON"), after having disconnected the laser (T_ {off}) can be calculated by the minimum scope from which reflections to intensify are not desired  (R_ {min}), multiplied by two, and divided by the speed of the light (C).

According to an embodiment of the present invention, the laser generator provides pulses successively narrower and, even so, by means of the implementation of imaging technology by door switching, the same characteristics are achieved as with a greater pulse width.

According to some embodiments, the The present invention includes a method for improving yields of a night vision imaging system that is based on imaging with switching gate. This improvement is achieved by providing an intensification capacity depending on the scope of relevant objects from the system, thus overcoming the problems of glare that result from "irrelevant" reflections.

According to an embodiment of the present invention, the provision of the capacity of intensification depending on the scope of relevant objects, generating momentum with a certain form or, in other words, a impulse with a certain design from the light source of the system.

According to an embodiment of the present invention, the provision of the intensification capacity is achieved depending on the scope of relevant objects by means of a dynamic change, where the dynamic change is implemented at the level of a single frame of the Video image, taken by the system. Dynamic change such as the opening time of the image intensifier and / or the pulse width of the
To be.

According to another embodiment of the present invention, the provision of the capacity of intensification depending on the scope of relevant objects of the system, by controlling the number of exposures and the laser / intensifier time (above the level of a frame of a video image) and / or by image processing.

According to some embodiments, the The present invention incorporates a method to overcome the glare from similar systems installed in vehicles that advance. This is achieved by the application of techniques statistics and / or by synchronism techniques implemented in the systems.

According to some embodiments, the The present invention includes a method for complying with the radiation safety requirements, adjusting the intensity of the beam emitted from the light source of the system with the speed Cruising vehicle.

According to some embodiments, the The present invention includes a method to overcome flowering because of the local darkness at the entrance of the system camera, implemented by a spatial light modulator (for example, MMS, LCD, Suspended particles), with or without image intensifier (for example, through a CMOS / CCD camera, and a pass filter narrowband adapted to the wavelength of the source of light). In another embodiment, the present invention provides a method to overcome the florescence using polarization of the light.

Brief description of the drawings

The present invention will be better understood and will appreciate in a more complete way, from the following detailed descriptions, taken in conjunction with the drawings, in which:

Drawing No. 1 is an illustration in sight top of an overview of the imaging system at night, installed in a vehicle, in accordance with this invention.

Drawings 2 to 4 describe various installation configurations within a vehicle, of a night imaging system, according to some embodiments of the present invention.

Drawings 5 to 7 describe problems of glare that are overcome by the formation system of night images, according to some embodiments of The present invention.

Drawing No. 8 schematically describes a example of an embodiment of the training system of night images, according to a preferred embodiment of the present invention.

Drawings 9-25 describe various techniques to overcome the problem of flowering, which are treated with the night imaging system, according to some embodiments of the present invention.

Drawing No. 26 describes a specific technique for automatic synchronization, according to a mode of embodiment of the present invention.

Drawing No. 27 illustrates the scope of safety of a laser beam coming out of a moving vehicle, okay with some embodiments of the present invention.

Drawing No. 28 illustrates a method to overcome the fluorescence in the system, due to the local dimming of certain areas of the camera, according to an embodiment of The present invention.

Drawing No. 29 illustrates a method to overcome fluorescence in the system, using polarization d the light, according to an embodiment of the present invention.

It will be appreciated that for reasons of simplicity and clarity of illustration, elements illustrated in the drawings They have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated with with respect to the other elements, for reasons of clarity. Further, Where appropriate, numerical references may be repeated between the drawings to indicate corresponding elements or analogs throughout the series of views.

Detailed description of preferred embodiments

The following description is presented to enable the person skilled in the art to make and use the invention, as offered in the context of a particular application and its requirements. For those skilled in the art, various modifications to the embodiments described will be apparent, and the general principles defined herein may be applied to other embodiments. Therefore, the present invention is not limited to the particular embodiments illustrated and described, but is intended to be in accordance with a broader scope, consistent with the novel principles and features disclosed herein. In other examples, well-known methods, procedures and components have not been described in detail, so as not to overshadow this.
invention.

Referring to drawing No. 1, the drawing constitutes an illustration of a general configuration of the night imaging system 10, in accordance with an embodiment of the present invention, installed in a vehicle 20. The vehicle may be a vehicle that travel by road, an off-road vehicle, or a vehicle that travels in any other appropriate environment. The system 10 could include, for example, a light source in the wavelength, preferably not visible, such as in the wavelength 30 near the infrared. The system may include a camera 40 for imaging the reflections from the light source, for example, at the infrared wavelength. For example, camera 40 could be a CMOS camera or a CCD imaging system, etc. The system 10 could include the control apparatus 60 to control the video camera 40 or other system components. The camera 40 can adapt to images by door switching. The presentation apparatus 50 could also be arranged to present the images received in the camera 40 of
video.

Light source 30 at wavelength 30 does not visible (for example, at the near infrared wavelength),  you can illuminate a selected area, for example, in front of the vehicle 20, as indicated, for example, with the scope 65. It is possible to use, for example, a narrow band light source, just like a laser Another possibility is to use a series of diodes, or a broadband light source, such as a series of LED or even a light source that provides visible light. The light source 30 may be located inside the vehicle (as illustrated in the drawing) or outside the vehicle 20. Alternatively, the light source 30 can be placed anywhere you can allow light transfer to a selected range or objective, for example (not illustrated in the drawing) through one or more optical fibers

The camera 40 can receive reflections from the infrared energy that originates from the light source (if by example a light source not visible in the system is used), and can convert the reflected and absorbed photons of an image of video in the Field of View (FOV). It is possible to use, by For example, a CCD / CMOS video camera with or without intensifier images. The camera 40 may include an image intensifier, for example, in the case where the link is directly linked camera with the display apparatus 50 (as described in continuation with respect to drawing nº 3).

The presentation apparatus 50 can be included or set up in a Presentation in the High Part (HUD), which can present, for example, the image received from camera 40 of video in front of the driver's eyes in the field of vision of the driver. This can allow the driver to observe simultaneously the road in front of him and the presentation of the formation of night images, without having to alter the orientation of your head. Alternatively, it is possible to apply the apparatus 50 of presentation as a presentation at the bottom, by example, as an LCD display unit mounted near the car dashboard or any other appropriate place. The signal transmission to the display apparatus 50 may be carried out in various ways, for example by connecting a signal of analog or digital video to the presentation apparatus 50, or by a direct link of the video camera 40 with the apparatus 50 of presentation. Moreover, in order to strengthen the attention of the driver, or the clarity or effectiveness of the transmitted data, symbolic icons representing objects of a theoretical field of vision, in an image or view presented. By example, you can add icons to a presented image, which could include, for example, trees, signposts, barriers, pedestrians, etc.

Referring to drawings 2 to 4, the drawings describe various mounting configurations of the night imaging system 10, in accordance with an embodiment of the present invention, within the vehicle 20. The vehicle 20 it could be a vehicle traveling on the road, an off-road vehicle, or a vehicle for traveling in another suitable environment (such as a ship in a port, a train traveling on a railroad or a plane approaching an airstrip or sliding down a track). Drawings 2 to 4 are related to the system 10 described with reference to drawing # 1 and, therefore, the same number of
components.

Drawing No. 2 describes a configuration in which the display apparatus 50 is in a HUD configuration, which is mounted, for example, in the lower section of the window 60 of the vehicle. The light source 30 may be installed, for example, in the upper internal section of the vehicle, near the rearview mirror 70 of the car. The video camera 40 may be, for example, installed in the upper section of the vehicle (next to the light source 30). It will be appreciated by persons skilled in the art, that the light source 30 may also be installed elsewhere in the vehicle (for example, in the headlights, in the grille, in the side mirrors, or in any other appropriate place Thus, in the event that the light source is incorporated in a hidden place, the light can be transmitted by an optical fiber, for example, to the front side of the vehicle, where the beam (or beams) of light can exit. Grouping 80 of System Instruments 10 is located, in the example drawn, behind the instrument panel of the vehicle.Other configurations (which are not illustrated) may include mounting system 10 as part of a system that looks back at the vehicles, trucks etc. (operating while driving in reverse gear), or of the system package 10 inside the side mirrors of the vehicle or as a replacement for such
Mirrors.

Drawing No. 3 describes another configuration of the system 10, in which the display apparatus 50 is in a HUD configuration In this specific configuration, screen 50 is installed in the central section of the front window of the vehicle (thus allowing the passenger to be seated next to the driver can use the system). An intensifier 45 images, which can be built into the camera, can be mounted near the display apparatus 50, which is functionally connected to the presentation apparatus 50, or it can be integrated into the presentation apparatus 50. Such configuration may obviate the need for a CCD / CMOS camera as part of set 40. The present configuration can be applied, for example, to flat optics technology based on the holography. Such technology is described, for example, in the Patent Application document WO9952002, and allows the transmission of the image from the image intensifier 45 to a HUD 50, without the need for a CCD / CMOS camera. In the configuration current, image intensifier 45 is directly linked with flat optics and, using holograms for example, transmits an image to a selected place, for example in front of the field of driver's vision Moreover, a device can be used LCD screen, which can allow the presentation of the image received from image intensifier 45.

Drawing No. 3A describes an example of a optical scheme of the aforementioned configuration of flat optics based on holography.

Image intensifier 45 may be installed anywhere in the front section of the vehicle. The Light source 30 may also be mounted in this configuration, for example in the upper internal section of the vehicle, near the 70 rearview mirror of the car. Similarly, with respect to This configuration will be appreciated by experts in the technique that is also possible to mount the light source 30 in any other appropriate place inside or on the vehicle (for example, in the headlights, on the grid, in the mirrors sideways, or anywhere else) and direct the light through an optical fiber towards the front of the vehicle, where you can be emitted the ray of light).

Drawing No. 4 also describes a configuration in which the display apparatus 50 is of the type HUD In this specific configuration, the apparatus 50 of presentation uses direct filtering of the image from the output of the image intensifier 45 towards the window 60 of the vehicle, or to the projection surface 90, for example by a reflective optical assembly 95 or projection optics, which you can divert the image to the window 60 of the vehicle or to the projection surface 90.

Referring to drawings # 5 - 7, the drawings illustrate various components and methods to avoid the "glare" to other drivers, according to some embodiments of the present invention. The drawings concern the system 10 described with reference to drawing # 1 and, therefore, the same numbers are used for the components.

The implementation of a training system for night images at near-infrared wavelength, For use in vehicles, it requires overcoming problems of flowering in the environment, self-dazzle, and glare from similar imaging systems at night installed in other vehicles. The description presented then with respect to the phenomenon of glare you can facilitate an understanding of techniques to overcome such problems, as specified below in the framework of the Detailed description of the invention.

The camera 40 for the wavelength of infrared (when referring to drawings # 1 - 4) could enter a saturation state due to the existence of light sources in the field of vision of the system, such as front lights (including the front lights of vehicle 20, in which the system 10) and the street lamps are installed. The chamber saturation could blind the formation system of night images. These light sources emit energy not only in the visible spectrum, but also in the wavelength not visible, which could cause saturation and glare. So by example, the halogen tungsten bulb, which is used normally as a vehicle front light, it emits most of its light in the infrared wavelength. In drawing # 5, for example, the spectral emission curve of a light is illustrated front, where the X axis indicates the wavelength of the radiation of the front lamps, and the Y axis indicates the intensity issued.

Referring to drawing 6, the drawing illustrates a scenario in which the vehicle 20, in which the system 10 in accordance with the present invention is installed, travels along the rail 110, where there are additional light sources, that emit energy in the near-infrared wavelength. In the illustrated example, the rear lights of a vehicle 120, which is currently moving in front of the vehicle 20, and the front lights of a vehicle 130, which is about to pass in front of the vehicle 20, provide additional light sources. In the range between vehicle 20 and dazzling vehicles 120 and 130, there are two objects 140 and 150, which are absolutely identical in size, and whose night vision system 10 attempts to detect and form images of the
same.

In the precise instant of time illustrated, the distance between object 140 and vehicle 20 is shorter than the distance between object 150 and vehicle 20. Therefore, in a normal situation, without implementing certain techniques that constitute the subject matter of the present invention, the intensity of the radiation, which will be reflected from object 140 to the system 10, will be greater than the intensity of radiation that can be reflected from object 150 to system 10. This is because the closer an object is to the lighting source 30 (in this case, reflector 140), more light picks up the lens of entry.

Below is an example of a calculation of light intensities emanating from various objects:

one

Referring to drawing 7, the drawing describes a scene similar to that illustrated in drawing # 6. Assuming that an active system 10 ('10) of night imaging in vehicle 130, which can be identical to the 10 night imaging system installed in vehicle 20, the movement of the vehicles, ones towards others, you can expose camera 40 (see drawing # 1) in one of the vehicles to the beam emitted from the approaching vehicle and vice versa.

Due to the fact that the intensity of the emitted energy is several times higher than the intensity of the energy reflected from the environment, chamber 40 (see drawing # 1), which is installed in each of vehicles 10 and 130 , as part of systems 10 and 10 respectively, can be saturated. The saturated chamber may not allow the distinction of reflected light from the environment. A similar phenomenon in the chamber 40 may also be caused by the taillights of the vehicle 120. A glare problem could also occur when the system installed in the vehicle 130 is different from the system 10, but still emits beams of the same length of wave or
Similary.

Referring to drawing 8, the drawing illustrates an embodiment of the formation system 210 of night vision images, in accordance with the present invention. The system comprises a light source, such as a generator 220 laser (for example, a diode laser); a camera that includes, for example, an image intensifier 230 capable of switching (for example, an ICCD / ICMOS switching); a filter 245 narrowband installed at the entrance of intensifier 230 of light, and a controller 240, which controls the transmission 220 of the laser and image intensifier switching 230.

Optionally, system 210 also includes light sensors operating at visible wavelength 250, to determine the level of ambient light (for example, to identify day / night situations), a pulse detector 260 to detect the presence of active formation systems of night vision images in the field observed by the system, an interface 270 with the data channel of the vehicle computer, and an image processing unit 280. Unit 280 of image processing can generate a video signal that is transmitted to the system presentation apparatus 50 (not illustrated, see drawings # 1-4, set 50). All the system receives power from a power supply 290 of Energy. The power supply 290 receives, by example, energy from the vehicle and converts the levels of input voltage at the required voltage levels of the system sets specified above.

The laser generator 220 can serve as a source of light in the proximity of the infrared wavelength. He laser can illuminate the area in front of the vehicle, whose observation is desired while driving. When lighting at the wavelength near the infrared, the image produced has a high level of contrast, substantially equal to the level achieved in the range visible, which allows you to read the road signs. Lightning laser reinforces the retro-reflective paint of the road (lane lines, stop lines, etc.) and in the signs, as well as reflective lights of cars. Sample all visible lights of cars and the road.

In order that the training system of night vision images, according to an embodiment of the present invention approximates the maximum efficiency, the width of the laser pulse produced by the laser generator 220 must be calculated as a function of the visibility field required by the driver (see calculation example with regarding drawing 11). Image intensifier 230 with switching capacity, can intensify the absorbed light, and You could receive an image even in a dark environment. He Image intensifier 230 may allow switching fast

Controller 240 can control source 220 Laser and image intensifier 230. The role of controller can be allow synchronism between the operation of the laser generator 220 and the operation of the Image intensifier 230. Controller 240 may allow also the control of the various parameters of the laser pulse, for example, the impulse start control, the control of the pulse duration (pulse length), and mode control of the impulse (for example, the frequency and the rising edge and / or of lowering or the shape and design of the impulse). The 240 controller could also allow rapid opening and closing of the intensifier 230 image, according to techniques to eliminate the glare, which are specified below.

Controller 240 may receive indications from a light sensor in the visible spectrum 250. The controller 240 can be related to one or more sensors (for example of the type of photosensor). Sensor 250 could provide indications with regarding the level of ambient light (for example, to identify day / night situations) to operate system 210 of consistent way. In case the sensor 250 identifies a night situation, it would be possible to continue using the sensor (or an additional pulse sensor 260) for detect similar nighttime imaging systems active in the zone. The detection of active systems can be crucial for purposes of synchronism and to eliminate mutual glare, as described below with respect to prevention techniques for florescence.

Controller 240 can receive data from a vehicle data channel, which may include information such as Cruising speed and steering wheel tilt, which can be used to determine the level of the laser pulse, with the in order to avoid security risks (as described below in relation to security techniques).

A treatment unit 280 may be arranged of images, thus allowing the system 10 to overcome problems of image quality and flowering through techniques of Image processing. Image intensifier 230 with switching capacity can be, for example, a camera ICCD / ICMOS with switching. The video signal from the CCD / CMOS camera, could reach 280 treatment unit images in which a correction of the quality of the image and elimination of flowering, as detailed to continuation. After image processing, unit 280 of Image processing can deliver a signal from the output analog or digital video (for example RS 170), for the purpose of presentation.

A band pass filter 245 may be provided narrow to selectively allow light transmission in the intensifier 230. The transmission can only take place when the reflected light is approximately wavelength of the laser 220. The system can only transmit the length of wave emitted by the laser 220, or at least ensure that the energy reflected from the laser pulse is substantially higher than the energy approaching intensifier 230 from a source that emanates from an active source of ambient light. Filtering of all wavelengths, with the exception of a length of laser center wave 220, can reduce the influence of such light active environmental (from continuous wave sources or from AC lamps, such as the front lights of the vehicle, street lamps, etc.). Thus, the resistance of the system 210 to the fluorescence could be improved when a 245 filter is incorporated narrow band

However, by reducing the influence of light ambient by the narrow band pass filter 245, whose length center wave is the laser wavelength 220, it might not be enough. In this case, additional ways of carrying out the night vision imaging system according to the present invention may apply additional techniques, with the in order to improve the resistance of the system to flowering, as specify below.

As clarified with respect to the drawings Nos 5 to 7, a vision imaging system nocturnal for vehicles, which allows to intensify the reflection as a function of the scope from it, could reduce the risk of glare from nearby reflections and therefore increase the dynamic range of the system 10. The performance of a system of Night vision imaging can be improved by creating a variable sensitivity depending on the scope. In this way, less intensification or less sensitivity to reflections from nearby sources, as opposed to reflections from remote sources.

Referring to drawings n ° 9 a 25, the drawings illustrate techniques to overcome the problem of glare, with which the system of night imaging according to this invention, in addition to the intensification capacity, as a scope function. The related technique is applicable, by example, in the embodiment of the present invention that has described with respect to drawing # 8 and therefore, it is preferred Use identical component numbers.

Drawing No. 9 describes a graph of the programmable sensitivity or time gain (TPG) for a range given, where, as the range increases, the sensitivity is raise.

Drawing No. 10 describes an example of a desirable sensitivity graph for a night vision imaging system. For example, a reasonable requirement for a night vision imaging system intended for a vehicle traveling at high speeds (for example, 120 km / h) is the detection of a human figure in a field of about 300 meters from the vehicle in which the system is installed. In addition, the detection of a vehicle should preferably be detected in a field of about 450 meters from the system. The level of reflection that image intensifier 230 (see drawing 8) can reach from a vehicle can in any case be substantially stronger than the reflection from a human figure, because the illuminated area is different in size and reflectivity and because it can be assumed that in a vehicle there are active sources of light that allow detection (for example, front lights or taillights). This indicates that there is no need for high intensification in order to detect a long-range vehicle. Under these circumstances, the graph in drawing # 10 describes a function in which the sensitivity at a range of 300 meters rises, and beyond 300 meters gradually declines, to a distance of about 450 meters. The system can therefore receive reflections of the light pulse (i.e., the laser pulse) only when these reflections are within the range of up to approximately 450 meters. At the same time, the system can rely on the input of energy emitted from active light sources with a greater range, such as the continuous wave front lights, which in any case are radiated from vehicles at a greater distance. In addition, the natural scattering of light illumination (i.e. laser illumination) can decrease sensitivity in a range.
far.

The sensitivity chart, depending on the scope, as mentioned above, can be obtained by system 10 applying various techniques (individually or in possible combinations).

Referring now to drawing No. 11, which refers to a graph (in the time domain) that describes a technique to obtain the sensitivity depending on the scope, that of the time between the width of the laser pulse and the opening time Image intensifier For each specific scope, it obtains a different overlap time between the opening of the Image intensifier and laser lighting time.

The examples ignored the radiation relationship returned / dimming of the light, by the law of inverse squares and atmospheric conditions In the example mentioned above the light source is a laser generator that provides a boost of To be. The width of the laser pulse (T_ {laser}) can be determined according to the depth of field from which a minimum level of reflections is required (R_ {0} - R_ {min}) divided by the speed of light in the relevant medium (C) and multiplied by two. R_ {0} is the range from which they arrived, for the first time, the reflections to the image intensifier of the system, while in the connected position (ON), where those reflections are the end result of the full extent of the pulse width that passes entirely over the target located in this range R_ {0}. Up to the reach R_ {min}, the reflections that are emitted from the objectives within this scope You will find a disconnected image intensifier (OF). He Image intensifier shutdown time (T_ {off}) immediately after sending the laser pulse, it can prevent the Reflection input from close range (thus preventing self-glare due to reflections nearby). In other words, the disconnection time can be determined according to the scope from which they are not desired reflections (R_ {min}). The disconnection time is calculated as this range multiplied by two and divided by the speed of the light (C). The disconnection time can be determined as a lighting range function of the front headlights vehicle (the input of reflections from this scope is not necessary, since it is observable in any case by the lights front of the vehicle).

The time of the opening state of the image intensifier (T II), in particular the period of time during which you receive reflections from the remote range, it can be twice the depth of field (R_ {max} - R_ {min}) divided by the speed of light (C) and multiplied by two.

Referring now to drawing No. 12, which it is related to a graph (in the scope domain) which illustrates the ability to observe according to the example, illustrated in drawing 11, R min is the blind range. Since this area, which is in front of the system, there may not be any input of reflections generated by the laser pulse. This is because the laser pulse propagated (forward) in the air, subsequently passed the required distance to the former images, while the system was still blind to the reflections generated by the laser pulse that collide with any object as they approach this range, having been the Image intensifier in the "OFF" position. Therefore, R_ {min} is the minimum range, from which the reflections can find the image intensifier in a "open" state. This is the minimum range, in which it follows existing the laser pulse while the intensifier of Image is switched to an "open" state. R_ {max} is the minimum range, from which the sensitivity is still in a maximum. Element 301 is an object that can be found something behind the range R_ {min}. Body 302 is an object to find further, at the end of the range R_ {max}.

To understand how sensitivity is achieved With the value of the scope, it may be necessary to examine how they receive reflections from those objects that are located at a distance between R_ {min} and R_ {max} (in the example illustrated, 301, and 302).

Referring now to drawing No. 13, which shows a graph (in the scope domain) illustrating a specific moment, in which the laser pulse 310 has just finish transferring object 301 and continue moving forward (now begins to transfer object 302).

Reflections from object 301 can be received at the time the image intensifier of the system is switched to the open state, even before all the width 310 of the impulse passes through object 301. Therefore, you have a lot of time in order to receive reflections that can be intensified from remote object 302, but only a limited intensification time is available for reflections from the nearest object 301.

From the specific time illustrated in nº 13, assuming the image intensifier is switched to a been open just before a short time it was energy reflected from object 301 (provided the momentum 310 is still on it), and the energy is also reflected continuously from object 302 (which is now transferred by the impulse 310 that advances).

As a result of this, the total energy introduced into the image intensifier as a result of the reflections from object 301 is related to the duration of the time in which the impulse passes an object 301, while The image intensifier is in an open position.

Referring to drawing No. 14, the drawing shows a graph (in the scope domain) describing a specific time later, a time in which the laser pulse 310 would have finished completing its passage through object 302 and continues its advance propagation.

From the specific moment illustrated in the drawing nº 14, assuming that the image intensifier was in open state, reflections from object 302 (provided that the impulse 310 is on it) and is no longer reflected from the object 301 (because impulse 310 has already passed it).

Consequently, it may be possible to reach a quantitative result in which the intensity of the reflection absorbed from object 302, to be found in scope maximum R_ {max}, may be substantially greater than the amount of reflection received from object 301. This is because the amount of reflection received (energy) is determined according with a period of time during which the image intensifier  is in the "ON" state (connected) and the object is reflecting

In other words, the laser pulse 310 can stay on object 302 for a longer time than on the object 301, in a state in which the image intensifier of the system introduces reflections. Therefore the intensifier of image introduces more energy from an object close to range maximum R_ {max} (302) than from an object close to the system (301).

Drawing No. 15 is a graph of the sensitivity of the system depending on the scope. R_ {0} is defined as the optimum range from which the sensitivity depending on the range, for example the time-programmable gain (TPG), remains constant to the desired range R_ {max}. In other words, R_ {0} is the optimal range of the system, from which, for the first time, the reflections reached the image intensifier of the system while in the "ON" (connected) position, where those reflections are the result end of the entire range of the pulse width that passes in its entirety, over the target located in this range R_ {0}. R_ {min}, R_ {0} and R_ {max} can be calculated accordingly-
mind:

2

where T_ {laser} is the length of impulse time, and T_ {off} is the period of time in the which image intensifier remains in one position "off" after the end of the pulse transmission. Any Professional skilled in the art will appreciate that the equations before mentioned are obtained simply from the calculations of T_ {off}, T_ {II} and T_ {laser} as mentioned additionally in the foregoing. In addition, the final results, either in time ownership or in scope values, they can be refined or, in other words, custom made, and by therefore, pure calculation should be considered only as the way recommended by the present invention to define substantially those values of scope L over time. Such Custom refinement or creation will be described from here, and you might consider for example, take into account the specific environmental conditions, vehicle speed, specific characteristics of the different objectives expected find in different scopes, changing the way of saying laser pulse, etc.

The graphic illustrated in drawing 15 may not be an ideal graphic, because the laser pulse that fades away far illuminates objects beyond the range R_ {max}, although there may be no need to illuminate them. In addition, and what is more important of the techniques that follow, the graph illustrated in the drawing # 15 may not be an ideal graphic, because the sensitivity remains constant between the optimum range R_ {0} to the desired range R_ {max}. It is possible to reduce the system sensitivity to receive the reflections that originate beyond the range R_ {0} by other techniques. Such techniques include changing the format or form of the impulse. laser, changing the operating time of the intensifier of image, and changing the period of time / width of the laser pulse. These techniques are described below.

Referring now to the drawings n ° os 16 to 18, in which graphics are offered that illustrate a technique of according to which a laser pulse is generated with a certain shape or design. In other words, drawings 16 to 18 illustrate the ability to change the shape of the laser pulse gradient, with in order to achieve maximum system sensitivity in the optimal range required R_ {0}.

In accordance with the scenarios illustrated by the drawings 11-15, in the event that a Laser pulse shaped or designed, can even be received by the image intensifier a smaller number of photons that would be reflected from object 301 (which is in the short range) and a greater number of photons that are reflected from object 302 (in the long-range). This may occur because the momentum is will remain on object 302 for a longer time than on object 301, and / or due to the shape of the laser pulse (i.e., shaped or design) while the laser intensity at the beginning of the impulse is higher than at the end of the impulse.

Drawing 16 is a graph of impulse 360 of laser with a certain shape or design (in the time domain, measured from the point of view of system exit). The duration of time T1 is the time in which the system transmits an impulse of laser with the maximum intensity. The duration of time of T_ {wave} is the time interval in which the intensity of the Laser pulse (intentionally) decreases in a way shaped or designed. T_ {off} is the time interval in the which both the image intensifier (see component 230 of the drawing no. 8) and the laser generator (see there in component 220), they are in the "OFF" position. T_ {II} is the time interval in which the image intensifier is Open and receive reflections.

Drawing No. 17 is a graphic (in the domain of scope) of the advance of the shaped or designed laser pulse. He graph describes a specific point in time, the moment in the which one impulse collides on the target within the short scope (R_ {min}), but the reflection will take a while additional (T_ {off} divided by two), in order to reach the Image intensifier At that time, the intensifier of image begins to collect photons according to the place where the shaped or designed laser pulse must be in the free space. The photons that are in the range of R_ {min} are photons that come out at the end of the impulse and that were able to go to reach S_ {1}, at the same time that the Image intensifier The photons that are between the S1 range and the scope S2 (in the range R_ {wave}), are photons that they left at the beginning of the conformed or designed impulse drop To be. The photons that left the laser generator with the maximum intensity at the beginning of the range S_ {3} reached by the impulse lighting (and they are traveling in space R_ {with}).

It will be appreciated by experts in the technique that the range R_ {min} depends on the period of time from T_ {off}, the period of time from the end of the pulse to Image intensifier opening. The photons that leave at end of the impulse and that can return to the camera after a period of time shorter than T_ {off}, may not reach the intensifier Image in an active state. Therefore, those photons may not be intensified and an R_ {min} range can be obtained from the system, in a range from which impulse reflections Lasers may not be intensified. For example, a determination that the time T_ {off} can be 100 nanoseconds, it would give as result that the system would not make the intensification of reflections from the short range of up to 15 meters of distance from him.

In addition, anyone skilled in the art understand that a form of the impulse of "1 / R2", at least in terms of minimizing reflections from the object in a short range while the image intensifier is in an "open" state, and the aforementioned "sawtooth" impulse is shifts in the time domain while at the same time Ignore the dimming of the laser lighting.

Drawing No. 18 is a sensitivity chart of the system / TPG depending on the scope, where the technique is applied of the shaped or designed laser pulse (see and compare the drawing nº 15, in which the technique was not applied). Consequently, R_ {wave} is the range from which the reflections generated by the shaped or designed laser pulse are received and intensified, R_ {1} is the extent to which the laser pulse intensity is stable (the gradient is the result of the different moments of overlapping times of passage between the impulse and the object, as explained above with with respect to drawings n 12 to 14).

Consequently, it is possible to further reduce the sensitivity of the system in short ranges, as potentially caused by reflections originating in short distances, producing shaped or designed laser pulses and using them in combination with the range and a time based technique in pulse width, to open the image intensifier, as described above with reference to drawings # 11
to 15.

Any person skilled in the art will understand that the fact that the implementation of the technique of conformed or designed impulses, allows to achieve an improvement of the system sensitivity depending on the scope (compared to the sensitivity achieved by the switching gate technique By herself).

Referring now to the drawings n ° os 19 to 22, these graphs illustrate a technique according to the which, in the course of obtaining a video frame, can change the width of the image intensifier opening and / or the width of the laser pulse. The starting point is the understanding that limiting the number of lighting pulses without compromise image quality, is the desired result with the in order to eliminate or reduce system sensitivity to sources environmental. In other words, in order to get the maximum system sensitivity in the range of interest, the fact is used that concerns a system based on a video frame (see, for example, in the embodiment illustrated in the Figure 8, the use of the ICCD / CMOS 230 switched), as a technology that inherently possesses the ability to control within single-level frame (see controller 240 of the drawing No. 8).

In vision imaging systems of the type studied previously, the camera for infrared wavelength (see drawing # 1, component 40 and drawing # 8, component 230) could be a video camera standard (for example, a CCD / CMOS). Such cameras work at a constant frequency of 50 Hz, 60 Hz, etc. this means that each second the camera takes 25 or 30 frames, etc. Because of provide an example, suppose the camera operates at 50 Hz, which means that the duration of an individual field is 20 milliseconds As noted above with respect to drawing nº 11, the scope of interest for the system can be of 300 meters, and therefore the width of the laser pulse plus the width of the image intensifier opening add up (for example) 3 microseconds In order to explain the techniques, the implications of the time interval T_ {off} may not be considered. This may require a cycle time of 3 microseconds without time gaps (i.e. wait times), between the end of the laser pulse and the "opening" of the Image intensifier According to the example before mentioned, it may be possible to transmit, in the course of the shot by the camera of an individual Field, up to 6666 impulses and for Collect 6666 times the photons in the image intensifier.

Drawing 19 is a graphic (in the domain of time) that describes the sequence of impulse cycles (L) and the photon collection (II). For an individual cycle, see drawing nº 11 (although ignoring the implication of the T_ {off}). May assume that the lower the number of cycles required for To obtain a quality image, the greater the capacity of the system to reduce or eliminate source influences environmental, since by increasing the number of cycles, you can increase eventually the potential exposure to sources environmental.

Referring now to drawing No. 20, which is related to a graph (in the time domain) that illustrates a technique according to which the duration of the laser pulse in a dynamic way in the course of obtaining of the individual frame. The total width of each of the cycles remains constant, although the width of the laser pulse is made narrower, the more the cycles in the domain of time, until the last cycle, in which, however, all the cycle width is equal to the first cycle, but the duration of the Laser pulse is very short, and the waiting time for it to open the image intensifier (see drawing 11 for the time T_ {off}), is very long. The rate of change, by increasing the wait time before the image intensifier switches to "ON" state, is equal to the narrowing of the laser pulse. By therefore, the scope from the system, where reflection from it does not intensifies (because the image intensifier is not active, see drawing # 11 - the range R_ {min}), can be increased This means that the system receives more reflections. from the remote distance and less from the short distance, and it Get a desired sensitivity for reach.

Referring to drawing No. 21, a graph (in the time domain) that describes a technique of agreement with which the duration of the intensifier opening of image changes in a dynamic way in the course of obtaining An individual frame. In addition, by this technique, the total width of each of the cycles remains constant, although the more short the duration of the intensifier opening is made image, more cycles advance in the time domain, until the last cycle, in which, the entire width of the cycle is equal to first cycle, but the duration of the intensifier opening of image is very short and the waiting time for the image intensifier (see drawing # 11, time T_ {off}), is very long. The rate of change, which narrows the opening time of the image intensifier while keeps the width of the laser pulse constant, it is the same at frame length Thus, the scope of the system, for which the energy reflected from it is not intensified (because the Image intensifier is not active), can be increased (see drawing # 11, the range R_min). This means that the system introduces more reflections from the remote distance and less from a short distance and, once again, you can get a desired sensitivity for reach.

Referring now to drawing No. 22, offers a graph (in the time domain), which describes a technique that overcomes the disadvantages materialized in the methods described above (for example, drawings # 20 and twenty-one). A disadvantage of the method according to the drawing nº 20, as the opening time of the Image intensifier can remain constant and therefore the system can remain sensitive to the influence of light environmental in those periods of time. A disadvantage of the method of According to drawing No. 21, it may be that the laser pulse remain constant, but some of the energy may not return to Image intensifier, thus leaving energy unused.

Also in the technique illustrated in drawing no. 22, the total width of each of the cycles remains constant, although the duration of the laser pulse becomes shorter the longer the cycles in the time domain advance and, simultaneously, the waiting time for image intensifier opening (see drawing 11, the time T_ {off}) also changes from in a dynamic way, the waiting time is done progressively longer (for example at a speed twice the duration of the shortening of the laser pulse). In this method, the time in the which image intensifier remains open and therefore liable to be influenced by the light emitted by the environment, it shortens, exploiting energy to the fullest.

Consequently, it may be possible to reduce the sensitivity of the system to glare, as a result of reflections that originate in short ranges. To adapt the system response graph to the desired graph (see drawing 15), a dynamic change may be required during process of obtaining an individual video frame, changing progressively the width of the intensifier opening of image and / or the width of the laser pulse and the delay between the Image intensifier and laser.

It will be appreciated by experts in the technique, that the aforementioned methods of affecting a change dynamic in the course of capturing the frame, that the width of the intensifier opening and / or the width of the laser pulse can be integrated and combined with the application of the method of deliver an impulse with form or, in other words, designed, coming from the system's light source in the range invisible (a laser diode, in the example explained above). The combined application of the techniques described above may contribute eventually to achieve the objective of carrying out the correlation between the actual system response graph and the desired sensitivity graph.

Referring to the drawings n ° 23 - 25, graphics are offered that illustrate techniques according to the which may be possible to eliminate the flowering originated from high intensity light sources, by controlling the number of cycles or, in other words, exposures, at the level of single frame In addition or alternatively, the implementation of the imaging techniques in the system can Eliminate florescence.

Referring to drawings No. 23 and 24, the graphics are offered (in the time domain), which show the capacity of the system controller (see drawing No. 8, controller 240) to dynamically reduce the speed of impulse cycles (L) and photon collection (II).

According to the example mentioned above (with reference to drawings n ° 10 to 22), in the  course of the capture by the camera of an individual Field, can it is possible to transmit, for example, up to 6666 pulses per field (or 13332 pulses per frame) and collect photons, for example, 6666 times in the image intensifier. However, also it may be possible to make fewer exposures in the course of the obtaining the individual field (see drawing no. 24, a field in the course of which only 100 cycles of exposition).

A reduction in the number of exposures could cause fewer photons to collect in the image intensifier and therefore can cause darkening of the entire image, so that areas with low Reflection may not be visible. Therefore, the number of Exposures must be controlled dynamically. It is possible to control the number of exposures by various methods, for example, of according to the ambient light level (an input that can be obtained from a sensor, such as sensor 250 in the mode of embodiment of the present invention described in drawing 8). Another control method is consistent with the current level consumed by the image intensifier (information that can be obtained from power supply unit 290 illustrated in the embodiment of the present invention, shown in the drawing nº 8). Another method that is applicable is the treatment of images, locating the zones in a state of saturation.

Referring now to drawing No. 25, provides a method for image processing with a number exposure variable in each frame. For this application, it you can use a camera faster than a CCD / CMOS camera standard. As an example, it can be assumed that the camera works at 100 Hz, which means that the duration of time of the Field individual can be 10 msec. (for example, a frame of 20 msec.).

This camera capacity can allow Acquisition of two frames. In a frame you can get a large number of exposures, and in the other frame you can get A small number of exhibitions. In the example illustrated in the drawing No. 25, the dynamic method that is the object can be implemented of drawing nº 22. In the first frame (2 fields), the system I could perform 1000 cycles and, in the second frame (2 fields), I could perform 50 cycles. The number of cycles can be determined, as established, by different methods, by example, according to the level of ambient light, according to the saturation state of the image intensifier tube, or of agreement with the treatment of images, locating the areas of saturation.

After obtaining the two frames by the techniques of image processing (which are applicable in unit 280 of image processing of an embodiment of the present invention, described in drawing # 8), it may be possible to create from the two frames, a combined frame. Dark areas can be combined from the frame with the highest number of exposures, and saturated areas can be taken from Frame with fewer exposures.

According to the illustrated example that shown in drawing No. 25, it can be assumed that the size of the Image is 4 pixels. In frame 1, which originates from a large number of cycles, the upper pixels are saturated (while the lower pixels retain a gray level reasonable). In frame 2, which originates from a small number of exposures, the upper left pixel is not It was saturated. In the combined image, you can combine the unsaturated pixels of frame 1, and saturated pixels of frame 2. Thus, a combined frame can be obtained, in which the number of saturated pixels may be lower and the quality of the Image may increase.

By implementing the above method, you can allow to enlarge the dynamic range of the system and provide high image quality even in a saturated environment. It will be possible appreciate by those skilled in the art that the treatment of images can also be done by implementing other methods of treatment. For example, through a camera even more fast, it may be possible to compare more frames.

As noted above regarding to drawing 7, one of the problems of glare with the which the present invention can deal with is the problem of glare by similar systems. Generally speaking, the Solutions to the problem can be classified into two groups, statistical solutions, which apply statistical techniques to decrease the likelihood of mutual glare, and solutions synchronous, in which the synchronization between the systems to prevent glare.

Possible statistical solutions for eliminate mutual glare between similar systems that cross each other (see drawing # 7) could include a reduction of the number of exposures in the course of obtaining images (with possible compensation for an intensity greater than laser or a higher level of intensification of the intensifier of image), a random or predefined change in the synchronism of cycles during the course of a frame, a change in frequency of exposure, or any combination of these methods.

Synchronous solutions to eliminate the mutual glare between similar systems that cross between yes, they allow such synchronism, that you cannot create a situation of glare. One solution may be the establishment of a communications channel between the systems (for example, in the range RF) In this way, systems can "talk" to each other. other. Another solution is an automatic synchronism.

Referring now to drawing No. 26, offers a graph that illustrates an automatic synchronization technique between two or more systems. Synchronism can be performed by a system that enters, from time to time, in a period of "listen", in the course of which the system gives up the cyclic sequence of sending laser pulses (L) and opening of the image intensifier (II). In the course of the period of "listen", the system may stop emitting laser pulses and collect input pulses (if any), which come from the other system. In the event that no impulses are received, the first system can resume activity at the end of its period of "listens". In the event that, in the course of the period of "listen", impulses will be introduced from another neighboring system, the first system could wait until the end of the sequence cyclic of the other system, and can resume its activity only at the end of the sequence of the other system.

In the example illustrated in drawing # 26, the first system, whose activity over time domain It is illustrated in the graphic above, you can perform a sequence cyclic of 50 exposures and can go into a state of "listens". In this method, a synchronism can be created between one system and the other system (see graphic below), while that approximately 50% of the possible exposure time of the Frame is assigned to each system.

The synchronization method explained It is previously applicable, for example, in one embodiment of a night vision imaging system of according to the present invention, which is described with respect to the drawing nº 8. In a vehicle in which the system is installed, it may be possible to mount, for example, two detectors 260 of impulses, a detector in the front of the vehicle and the second detector at the rear of the vehicle. With reference to the drawing No. 7, it may be possible to identify if the neighboring similar system it works in a vehicle (130 in that case) that moves towards the vehicle (20 in that case) or in another vehicle from the rear vehicle 20. As there is no danger of glare from the vehicle coming from behind the system, may not sync with him.

Synchronism can also be achieved. through a technique to share. For example, dedicating part of "listen" time of the frame to possible illuminations coming from other systems. In order to provide images reasonable, the system may require a part of the frame, and therefore part of the frame time can be used to "listen" purposes. When a system is not detected neighbor lighting, the system controller can decide randomly when the laser generator will start to illuminate within the extension of a frame. Moreover, with the detection, the system controller can start the transmission only after finishing the approaching lighting and at a randomly chosen moment after it.

Another technique that is applicable in order to eliminate a possible state in which both systems can start  to emit at the same time, is that each of the systems can also randomly change its start times of the Pulse transmission in each frame.

It will also be appreciated by expert people in the technique that, with the synchronism method, is possible synchronize with impulses that originate in other systems and that They work at different speeds. Moreover, it is possible to get synchronism by other methods, for example you can transmit a momentum of synchronism by any other system in any period of time, and the system that introduces them could adapt according to the momentum of synchronism received.

A training system of night images in accordance with the present invention, for meet selected security requirements against radiation (for example, in accordance with ANSI Z 136.1 of American Standard). How system 10 can be designed to be installed in a mobile vehicle, although it is unlikely that a person is standing in front of him, it is possible to change, okay With the cruising speed, the intensity of the light source emitted (for example, the intensity of the laser generator 220 described in the embodiment illustrated in the drawing No. 8). Thus, the intensity of the radiation is intended to be zero and completely safe in a situation where the vehicle is not is moving Information concerning cruise speed of the vehicle can come from the data channel of the computer of the vehicle (for example, of interface 270 illustrated in the mode of embodiment shown in drawing # 8). In addition to the data of speed, it is possible to take into account the steering wheel angle to adapt the light and intensity of it to the cruising angle and to the areas of interest of the driver.

In addition, even assuming that the light source is a laser considered as a continuous wave, the scope of safety during maximum operation of system 10 can be calculated, for example, in about 4 meters. To prevent the functioning while someone is potentially within This safety scope, the laser intensity can be adapted to the cruising speed of the vehicle. At speeds low, the laser can weaken and can close when the vehicle stops. When a vehicle is driving at high speeds, no problem meeting the scope of security, since the probability of people facing a moving vehicle, within this range, is quite light

How a laser beam can be cone-shaped divergent, the beam should not find any person within this reach. Drawing No. 27 shows the improbability of creating a security problem, since in the scope of security from the mobile vehicle 410, the laser beam leaving vehicle 410 travels at an angle that does not depart from the width of the vehicle. By therefore, it is unlikely that a person is in front of a mobile vehicle at that distance.

An additional optional means of complying with eye safety requirements, may be the implementation of a light source high in the visible spectrum, near the laser source, a source of light that can cause a person to be in the system proximity divert your gaze from the light source invisible.

It will be appreciated by experts in the technique, that it is possible to combine the method of adapting the speed Cruising to laser intensity, with the method of implementation of an additional dazzling light source in the laser proximity

Drawing No. 28 describes an additional method of overcome the fluorescence in the system according to drawing no. 8, by local darkening of certain areas in the chamber. In the input of the ICCD / ICMOS 230 switching, it can be installed a spatial light modulator (zone shutter) 510. The modulator 510 light can include an optical device, installed in the light intensifier input, and can allow blocking Regional light at the entrance to the light intensifier. Such optical device can be a liquid crystal (LC), a screen of suspended particles (SPD), a spatial light modulator (by example, an MMS), or any other suitable device. Using the optical device, it may be possible to eliminate the penetration of light or decrease the intensity of light, thus preventing camera saturation in certain areas.

Drawing No. 29 describes an additional method to overcome the flowering in the system according to the drawing No. 28, using the polarization of light. At the entrance of the ICCD / ICMOS 230 switched, a medium 610 of polarization (either in combination or without 510 shutter). He polarizer can only transfer light of the same polarization than the light produced by the laser source 220. As the sources of  glare mainly produce unpolarized light, the energy that originates from ambient light sources can be moderate, and the immunity of the system to flowering can to get better.

An additional method to overcome flowering in the system, according to an embodiment of the present invention is the application of a CMOS / CCD camera with capabilities shutter Such a camera might not lose energy while shutter, thus allowing the accumulation of energy in synchronism with the laser pulse, and thus providing system sensitivity It is a function of the desired detection range. This could be similar to an embodiment described with reference to the drawing nº 8, where a camera with image intensifier is installed commuted

It will be appreciated by experts in the technique, that the present invention is not limited to what is He has illustrated and described particularly in the foregoing. In its instead, the scope of the present invention is defined only by the following claims. For example, many of the above embodiments refer to a traveling vehicle by highway. However, other embodiments may be related to vehicles traveling off the road or in Any other suitable environment.

Claims (77)

1. An imaging system (10), for mounting on a vehicle (20), comprising: a source (30) of light, to provide a light energy in the form of pulses, defining said energy of pulse-shaped light a substantial width T_ {laser} of momentum, and a camera (40) to receive said energy from light in the form of impulses, reflected from the objects, being able to operate said camera with a switched detection of said energy of light in the form of impulses, reflected from the objects located within the depth of field from which you want to form images, said depth of field having a minimum range R_ {min}, said camera starting to detect light energy after a period of delay, substantially given by the time it takes for the width substantial impulse of said light energy in the form of an impulse, in reaching said minimum reach and in completing the reflection to said camera from said minimum scope; said system being characterized in that: said switched detection of said energy of impulse-shaped light, reflected from objects, defines a connection time interval (ON), T_ {II}, during which said camera receives reflections of the objects, a range of OFF time, T_ {off}, between two intervals of contiguous connection time, during which said camera does not receive reflections from objects, and a synchronization time between said connection time interval and the time in which said light energy in the form of momentum is reflected from objects located within said depth of field from which the images; in which said synchronization time defines the amount of overlap between said time interval of connection and said light energy in the form of impulse reflected from the objects, and said camera being able to operate so that creates a sensitivity based on a range for that system of imaging, through that time of synchronization, such that said overlap between said light energy in the form of momentum, reflected from objects, and said connection time interval, increases depending on the range to an optimum range, R_ {0}, of said depth of field from which images are taken, thus increasing the part of said substantial pulse width of said light energy in the form of impulse, reflected from objects located between that range minimum and said optimum range that said camera reaches during the connection time interval. 2. The system according to claim 1, wherein said camera operates in a manner that creates said sensitivity depending on the scope of said training system images, through said synchronization time, in such a way that said overlap between said light energy in the form of impulse, reflected from objects beyond that optimal range, and said connection time interval, is maintained  detectable depending on the scope, up to a maximum range of said depth of field from which images are taken, R_ {max}, thus maintaining part of said substantial width of the impulse of said impulse light energy, reflected from the objects located between said optimum range and said maximum range which said camera reaches during said time interval of Connection. 3. The system according to claim 2, in which said camera operates in a manner that creates said sensitivity depending on the scope of said training system images, through said synchronization time, in such a way that said overlap between said light energy in the form of impulse, reflected from objects beyond that optimal range, and said connection time interval, is maintained  substantially constant depending on the scope, up to said maximum range, thus keeping the part substantially constant of said substantial width of the impulse of said light energy in impulse form, reflected from the objects located between said optimum range and said maximum range that said camera reaches during said connection time interval. 4. The system according to claim 2, in which said camera operates in a manner that creates said sensitivity depending on the scope of said training system images, through said synchronization time, in such a way that said overlap between said light energy in the form of impulse, reflected from objects beyond that optimal range, and said connection time interval, decreases depending on the scope, up to said maximum range, thus decreasing the portion of said substantial pulse width of said energy of impulse-shaped light, reflected from the objects located between said optimum range and said maximum range that reaches said camera during said connection time interval. 5. The system according to claim 1, wherein said impulse light energy defines a impulse design and a form of impulse. 6. The system according to claim 5, further comprising a controller coupled with said camera and said light source, to determine and change at least one of: said delay time, said pulse width, said shape of the impulse, said impulse design, said time interval of connection, said disconnection time interval and said time of synchronization 7. The system according to claim 6, wherein said controller determines at least one of the following: said delay time, said pulse width, said connection time interval, said time interval of disconnection and said synchronization time according to at least one of the following: said depth of field, conditions specific environmental, the speed of said vehicle and the specific characteristics of the different objectives expected find in that depth of field. 8. The system according to claim 7, in which the determination of said controller is dynamic. 9. The system according to claim 7, in which the determination of said controller varies so increasing or decreasing over time. 10. The system according to claim 7, wherein said sensitivity depending on the scope comprises a dynamic change of a selected parameter among the group that it consists of: said form of the impulse, said design of the impulse, said connection time interval, said time interval of disconnection, said pulse width, said delay time and said synchronization time. 11. The system according to claim 10, wherein said controller determines said dynamic change of agreement with at least one of the following: said depth of field, said specific environmental conditions, said speed of said vehicle and said characteristics of the various objectives that are expected to be found in that depth of countryside. 12. The system according to claim 6, wherein said pulse width and said time interval connection are limited by said controller, to remove or reduce the sensitivity of said system to light sources environmental. 13. The system according to claim 10, in which: said pulse width, said interval of disconnection time and said connection time interval define a cycle time; Y said impulse light energy is sent with a duration of said pulse width, being delayed the opening of said chamber during the duration of said disconnection time interval, and the energy being received from impulse-shaped light reflected from objects, with duration of said connection time interval. 14. The system according to claim 13, wherein said pulse width is progressively shortened and said delay time is progressively lengthened, when the cycle time does not change, to increase said sensitivity depending on the range, when they accumulate impulse reflections for a frame
individual. 15. The system according to claim 13, in which said connection time interval is shortened progressively and said delay time progressively lengthens, when the cycle time does not change, to increase said sensitivity depending on the scope, when reflections accumulate of the impulses for an individual frame. 16. The system according to claim 13, wherein said pulse width, said time interval of connection is progressively shortened and said delay time is lengthens progressively, when the cycle time does not change, to increase this sensitivity depending on the scope, when accumulate impulse reflections for a frame individual. 17. The system according to claim 5, in which said pulse form comprises a more intense high at the beginning of said impulse than at the end of said impulse, to increase this sensitivity depending on the scope. 18. The system according to claim 1, in which: said pulse width starts at a time start, T_ {0}; Y said delay time is substantially defined according to the following equation:

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3

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in which c is the speed of the light. 19. The system according to claim 1, wherein said pulse width is substantially defined according to the following equation: 4 in which c is the speed of the light. 20. The system according to claim 2, wherein said connection time interval and said disconnection time interval are substantially defined according to the following equations: 5 6 in which c is the speed of the light. 21. The system according to claim 13, which also includes: at least one ambient light sensor, coupled with said controller; a pulse detector, coupled with said controller, to detect pulses that are emitted from a system similar to said system, mounted on a vehicle that about; an interface to a computer system of said vehicle, coupled with said controller; an image processing unit, coupled with said camera; a narrow band pass filter, coupled with said camera; Y a presentation apparatus, coupled with said image processing unit, to present images constructed from said impulse light energy, received by said camera. 22. The system according to claim 21, which also includes: a light polarizer, coupled with said camera; a spatial light modulator, coupled with said camera; Y a dazzling light source, placed nearby of said light source. 23. The system according to claim 21, in which at least one repetition of said cycle time It is part of an individual video frame, and several of these repetitions form a number of exposures per said frame Of video. 24. The system according to claim 23, wherein said controller dynamically varies said number of exhibitions 25. The system according to claim 23, wherein said controller varies said number of exposures according to a level of ambient light determined by said at less an ambient light sensor. 26. The system according to claim 23, wherein said controller varies said number of exposures according to a level of current consumed by said camera. 27. The system according to claim 23, in which the mutual glare between said system and a similar system that cross each other is eliminated by statistical solutions selected from the group consisting in: the decrease in said number of exposures by said controller; the change by said time controller of said cycle time during the course of said individual frame  Of video; Y the change by said frequency controller of said number of exhibitions. 28. The system according to claim 23, in which the mutual glare between said system and a similar system that cross each other is eliminated by synchronous solutions selected from the group consisting in: establish a communications channel between said system and said similar system; allow each of said system and said similar system go to listening modes from time to time, in the which said light energy is not emitted as an impulse during a listening period, after which period neither said system nor said similar system resume the emission of such light energy in form pulse, if no impulses were collected during that period of listen, and after which period said system and similar system wait until the end of a cyclic sequence of light energy in form of impulses before resuming the emission of said energy from pulse-shaped light, if impulses were collected during said listening period; Y make these systems change the time of pulse start transmission in said individual frames Of video. 29. The system according to claim 21, wherein said image processor comprises means for locate zones in said chamber in saturation state. 30. The system according to claim 23, wherein said image processor comprises means for Treat a variable number of exposures. 31. The system according to claim 1, wherein said camera receives several pulses of said energy of impulse-shaped light, reflected from objects during said connection time interval. 32. The system according to claim 1, wherein said impulse light energy is light not visible, and said light received in said camera is non-visible light. 33. The system according to claim 7, in which the intensity of said pulses of light energy is adjusted according to said speed of said vehicle, to Increase radiation safety. 34. The system according to claim 33, in which the width of a divergent cone of said is propagated light energy in the form of an impulse, with an angle that does not deviate of the width of said vehicle. 35. The system according to claim 1, wherein said light source is selected in the group that It consists of: a laser generator, a cluster of diodes, a LED grouping and a visible light source. 36. The system according to claim 1, in which said camera is selected from the group consisting in CMOS cameras, CCD cameras, a camera that has an intensifier switched image and a camera with shutter capabilities. 37. The system according to claim 21, wherein said presentation apparatus is selected from among the group consisting of: a presentation apparatus by the party upper (HUD), an LCD display device and a display device flat optics based on holography. 38. The system according to claim 22, wherein said spatial modulation of light is selected in the list consisting of: a zone shutter, a liquid crystal and a screen of suspended particles. 39. An imaging method for a system mounted on a vehicle, the method comprising procedures of: emit a pulse of light over an area objective, said light pulse defining a substantial width of the  impulse, T_ {laser}, receive at least one image from said impulse of light reflected from objects located within a depth  field from which images are taken, having such depth minimum range of field, R_ {min}, switch the detection of said at least one image received by a switched camera; where said procedure switching starts detecting said light pulse after a time delay that is given, substantially, by time which takes the substantial width of the pulse of said light pulse, in reaching said minimum range and completing the reflection back to said camera, from said minimum range, and intensify said at least one image received; said method being characterized in that: said switching procedure defines a connection time interval, T II, during which they receive reflections from the objects by said camera, an interval of disconnection time, T_ {off}, between two time intervals of contiguous connection, during which no reflections are received from the objects by said camera, and a synchronization time between said connection time interval and the time in which said light impulse is reflected from the objects located within said depth of field from which images are taken; where said synchronization time defines the amount of overlap between said connection time interval and said light pulse reflected from the objects, and said switching procedure is used to create a sensitivity depending on the scope of said system mounted on the vehicle, through said synchronization time, such that said overlap between said pulse of light reflected from the objects and said time interval of connection increases depending on the range to an optimum range, R_ {0}, of said depth of field from which images are taken, thereby increasing the portion of said substantial width of the impulse of said light pulse reflected from the objects between said range minimum and said optimum range, which said camera reaches during said time interval of
Connection. 40. The method according to claim 39, wherein said switching procedure is used to create said sensitivity depending on the scope for said system mounted on a vehicle, by means of said time of synchronization, so that said overlap between said pulse of light reflected from objects located beyond said optimal range and said connection time interval is maintained detectable depending on the scope to a maximum range, R_ {max}, of said depth of field from which the images, thus maintaining the part of said substantial width of the impulse of said impulse of light, reflected from the objects located between said optimum range and said maximum range that reaches said camera, during said time interval of Connection. 41. The method according to claim 40, wherein said switching procedure is used to create said sensitivity depending on the scope for said system mounted on a vehicle, by means of synchronization time, of such that said overlap between said reflected light pulse from objects located beyond said optimum range and said connection time interval, substantially maintained constant depending on the range, up to that maximum range, thus keeping part of said width substantially constant substantial impulse, of said impulse of light reflected from the objects located between said optimum range and said maximum range, which said camera reaches during said time interval of Connection. 42. The method according to claim 40, wherein said switching procedure is used to create said sensitivity depending on the scope for said system mounted on a vehicle, by means of synchronization time, of such that said overlap between said reflected light pulse from objects located beyond said optimum range and said connection time interval, decreases depending on the range, up to said maximum range, thus reducing the part of said substantial pulse width of said reflected light pulse from objects located between said optimum range and said maximum range, which said chamber reaches during said interval of connection time 43. The method according to claim 39, wherein said light pulse defines an impulse design and a impulse form. 44. The method according to claim 43, which further comprises the method of determining at least one between said delay time, said pulse width, said connection time interval, said time interval of disconnection and said synchronization time, according to the minus one of the following: said depth of field, the specific environmental conditions, the speed of said vehicle and the specific characteristics of different objectives that are expect to find in that depth of field. 45. The method according to claim 44, wherein said determination procedure is dynamic. 46. The method according to claim 44, wherein said determination procedure, in accordance with said depth of field, comprises the variation of said sensitivity in a growing or decreasing way with the weather. 47. The method according to claim 43, wherein said sensitivity depending on the scope comprises the procedure of dynamically changing at least one parameter selected from the group consisting of said design of the impulse, said form of the impulse, said time interval of connection, said disconnection time interval, said width of the pulse, said delay time and said time of synchronization. 48. The method according to claim 47, wherein said dynamic change procedure comprises the change according to at least some between: said depth of field, specific environmental conditions, the speed of said vehicle and the characteristics of different objectives that expect to find in that depth of field. 49. The method according to claim 44, wherein said pulse width and said interval of connection times are limited to eliminate or reduce such sensitivity to ambient light sources. 50. The method according to claim 47, wherein said dynamic change procedure comprises the sub-procedures of sending said light pulse with the duration of said pulse width, delaying the opening of said chamber with the duration of said interval of disconnection time, and receive said impulse of reflected light from the objects, with the duration of said time interval of connection, where said pulse width, said interval of disconnection time and said connection time interval define a cycle time of said switching. 51. The method according to claim 50, wherein said dynamic change procedure comprises the shortening of said pulse width progressively and the lengthening said delay time progressively, at the same time that is retained unchanged said cycle time, to increase said sensitivity depending on the scope, when they accumulate impulse reflections for an individual frame. 52. The method according to claim 50, wherein said dynamic change procedure comprises the shortening of said connection time interval and the lengthening said delay time progressively, at the same time that is retained unchanged said cycle time, to increase said sensitivity depending on the scope, when they accumulate impulse reflections for an individual frame. 53. The method according to claim 50, wherein said dynamic change procedure comprises the shortening of said pulse width and said interval of connection time progressively, lengthening said delay of time progressively, while retaining unchanged said cycle time, to increase said sensitivity as a function of scope, when impulse reflections accumulate for a single frame 54. The method according to claim 43, wherein said pulse form comprises a more intense high at the beginning of said impulse than at the end of said impulse, to increase this sensitivity depending on the scope. 55. The method according to claim 39, in which said procedure for issuing said impulse of light begins at the start time (T_ {0}); Y said delay time is calculated substantially in accordance with the following equation: 7 in which c is the speed of the light. 56. The method according to claim 39, wherein said pulse width is substantially calculated according to the following equation: 8 in which c is the speed of the light. 57. The method according to claim 40, wherein said connection time interval and said disconnection time interval are calculated substantially from according to the following equations: 9 10 in which c is the speed of the light. 58. The method according to claim 50, in which at least one repetition of said cycle time is part of an individual video frame, and several of those repetitions form a number of exposures for said frame Of video. 59. The method according to claim 58, which further comprises the method of dynamically varying said number of exposures. 60. The method according to claim 59, wherein said variation procedure comprises the adjustment of said number of exposures, according to a light level environmental detected. 61. The method according to claim 59, wherein said variation procedure comprises the adjustment of said number of exposures, according to a level of current consumed by an image intensifier used to said intensification procedure. 62. The method according to claim 58, which also includes the method of eliminating mutual glare between said system and a similar system that cross each other, through selected statistical solutions Among the group consisting of: decrease said number of exposures; a change in said time of said time of cycle, during the course of said individual video frame; Y a change in frequency of said number of exhibitions 63. The method according to claim 58, which also includes the method of eliminating mutual glare between said system and a similar system that cross each other, using selected synchronous solutions Among the group consisting of: establish a communications channel between said system and said similar system; allow each of said system and said similar system go to listening modes from time to time, in the which said light energy is not emitted as an impulse during a listening period, after which period none of the systems, the system in question and the similar system resume the issuance of said light pulse, if no impulses are collected during said listening period; and after said period, said system and said similar system wait until the end of a cyclic sequence of said light pulses, before resuming the emission of said pulse of light, if impulses were collected during this listening period; Y make these systems change the time of pulse start transmission in said individual frames Of video. 64. The method according to claim 58, which further comprises the method of treating images by locating zones in said camera in a saturation state 65. The method according to claim 58, which further comprises the method of treating images of a variable number of exposures. 66. The method according to claim 65, wherein said image processing procedure It includes the procedures of: take at least two video frames, one with a high number of exposures, the other with a number of Low exposures, by treating images of a number of variable exposures; determine the numbers of exposures to said at least two video frames; Y combine frames to form a single frame video, combining dark areas of the frames with a number high exposures, and saturated areas of the frames with a number of exposures low. 67. The method according to claim 39, which also includes the procedure of receiving several pulses of said pulse of light reflected from the objects, during said connection time interval. 68. The method according to claim 39, wherein said light pulse emission procedure it comprises the emission of non-visible light, and said receiving at least one image by said switched camera comprises the light reception not visible, in said switched camera. 69. The method according to claim 44, further comprising the method of adjusting the intensity of said light pulse, according to the speed of said vehicle, to control the safety of the radiation.
tion. 70. The method according to claim 69, which further comprises the method of propagating the width of a divergent cone of said light pulse, with an angle that is not deviates from the width of said vehicle. 71. The method according to claim 69, which further comprises the procedure of placing a source of dazzling light near the light source emitted by that impulse of light. 72. The method according to claim 39, which also includes the procedure of presenting said less an image on a presentation device, to present images constructed from said light pulse received by said camera. 73. The method according to claim 39, which further comprises the method of determining the light environment in said target area. 74. The method according to claim 39, which also includes the procedure of determining whether there is other pulses of light present in said target zone. 75. The method according to claim 39, which further comprises the method of filtering lengths of wave received from the reflections, using a step filter of Narrow band. 76. The method according to claim 39, which also includes the process of overcoming flowering  from other light pulses, by local dimming of the image intensifier input used for said intensification procedure 77. The method according to claim 39, which also includes the process of overcoming flowering  from other light pulses, by polarizing the light that enters the image intensifier used for said intensification procedure